You can definitely OD on gravity
When you want to know the limits of human endurance, work backward from world records. Stefanie Linder, a rep for the World High Diving Federation, told me that Red Bull extreme athlete Laso Schaller currently holds the dive height record, diving 192 feet and entering the water at 76 mph.
That, she stressed, was the, well, high-water mark and very much the exception to the rule. She didn’t recommend dives higher than 90 feet, already a terrifying distance to countenance. “The body is exposed to enormous forces,” she cautioned, “especially during entrance into the water.”
Contact with the water is the moment of highest risk. Turns out your back isn’t a big fan of being compressed upon entry. “While the parts of the body under water are in highest deceleration, the rest of the body above the water is still in full acceleration,” Linder explained.
In the edge case of needing to jump ship, there are some rules of thumb to consider. Absolutely do not dive head first, Linder stressed. She likewise assured me that no experienced diver worth his Speedo will go into the water horizontally or make a crash-landing of any sort. Aim for clear, deep water. And be aware of any obstacles along the way.
I once jumped from about 40 feet into the placid, cobalt-blue waters of Lake Huron, and it was simultaneously propulsive, thrilling, and petrifying. Having to jump ship, romantic notions of Jack and “You-jump-I-jump” Rose notwithstanding, is entirely another matter. Linder recommend that for those about to take the dive, “necessary strengths include courage, self-confidence,” and “extraordinary physical control.” Flailing is failing, people.